Physical and chemical changes are reversible and nonreversible changes. The release of carbon dioxide gas indicates a chemical change.
<h3>What is a chemical change?</h3>
A chemical change is a change in which a new substance is produced when the reactants react in the reaction mixture. The chemical produced cannot be reversed back to the reactants and hence, it is nonreversible.
The release of carbon dioxide is a chemical change as limestone and hydrochloric acid react with each other chemically and as a result, a new substance was formed.
Therefore, the production of carbon dioxide indicates a chemical change.
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<h2>Natural Abundance for 10B is 19.60%</h2>
Explanation:
- The natural isotopic abundance of 10B is 19.60%.
- The natural isotopic abundance of 11B is 80.40%.
- The isotopic masses of boron are 10.0129 u and 11.009 u respectively.
For calculation of abundance of both the isotopes -
Supposing it was 50/50, the average mass would be 10.5, so to increase the mass we need a more percentage of 11.
Determining it as an equation -
10x + 11y= 10.8
x+y=1 (ratio)
10x + 10y = 10
By taking the denominator away from the numerator
we get;
y = 0.8
x + y = 1
∴ x = 0.2
To get percentages we need to multiply it by 100
So, the calculated abundance is 80% for 11 B and 20% 10 B.
B. I’m sorry if I’m wrong ! Wasn’t sure about this question .
The gravitation field strength of Planet X is 10 times that of Earth's, as the object weight has increased 10 times. This is only possible if the planet is more massive or more dense (smaller diameter).
Therefore, the answer is C.
2H2S+2SO2 》》 4S+2H2O hope that'll help u
